Diff: main.cpp

Revision:

0:edd3bba01cdd

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Sun Oct 01 12:17:14 2017 +0000
@@ -0,0 +1,96 @@
+// Suggested partial solution for sending of amessage typed into termianl
+// by flashing the morse code for each letter in the message on LED
+// attached to D7 pin
+// Data entry and debug messages on PC terminal
+//
+// Chris Tipney September 2017 for module ELEC143
+//
+// Current limitations
+// (1) Only first 4 alpha characters and no numbers
+// (2) No warning if message length exceeded
+// (3) No trapping of non alpha characters (e.g. space or tab)
+//  
+// Suggested improvements:
+// Add rest of alphabet and numbers - rest of ASCII table must be trapped
+// Put suitable areas of code into functions
+
+#include "mbed.h"
+
+Serial pc(SERIAL_TX, SERIAL_RX);
+
+DigitalOut myled(D7);
+
+const int maxMessageLength = 20;        // max message length
+char message[maxMessageLength];   // Holds the message to be transmitted
+
+// array of strings to hold the morse codes (only A to D so far)
+// O = DOT (sound is DIT)
+// A = DASH (sound is DAA);
+// S = SPACE after a letter
+char codes[][6] = { "OAS",   // DIT DAA = A
+                    "AOOOS", // DAA DIT DIT = B
+                    "AOAOS", // DAA DIT DAA DIT = C
+                    "AOOS"   // DAA DIT DIT = D
+                    };
+
+int main()
+{
+    int position = 0;
+    
+    pc.printf("Morse message start...\n\r");
+    
+    while(1) {
+        // diaplay opening message and get message
+        printf("\n\r");
+        pc.printf("Please enter your message and press enter\n\r");
+        scanf("%s", message);
+        pc.printf("Message is %s\n\r", message);
+        
+        for (int i = 0; i < strlen(message); i++)
+        {
+            if ((message[i] > 64) && (message[i] < 91))     // upper case letter
+            {
+                position =  message[i] - 65;
+            }
+            else if ((message[i] > 96) && (message[i] < 123))   // lower case letter
+            {
+                position =  message[i] - 97;
+            }
+            
+            printf("%d:%c:%d:%d ", i, message[i], message[i], position);
+            printf("\n\r");
+            printf("%d %s ", position, codes[position]);
+            printf("\n\r");
+            printf("Letter is %c ", message[i]);
+            for (int j=0; j < strlen(codes[position]); j++)
+            {
+                if (codes[position][j] == 'O') 
+                {
+                    printf("DIT ");
+                    myled = 1;
+                    wait(0.15);
+                    myled = 0;
+                    wait(0.15);
+                }
+                   
+                if (codes[position][j] == 'A') 
+                {
+                    printf("DAA ");
+                    myled = 1;
+                    wait(0.45);
+                    myled = 0;
+                    wait(0.15);
+                }
+                
+                if (codes[position][j] == 'S')
+                {
+                    printf("<SPACE> ");
+                    wait(0.30);
+                }
+                //printf("%c ", codes[position][j]);
+            }
+            printf("\n\r");
+        }
+        
+    }
+}